J.R. S. answered 03/17/23
Ph.D. University Professor with 10+ years Tutoring Experience
B + HI ==> BH+ + I-
moles B present = 30.0 ml x 1 L / 1000 ml x 0.251 mol/L = 7.53x10-3 moles
To reach halfway of neutralization would require 1/2 x 7.53x10-3 moles = 3.77x10-3 moles
3.77x10-3 moles x 1 L / 0.150 mols = 0.0251 L x 1000 ml / L = 25.1 mls of HI